The present invention relates generally to surface maintenance or conditioning machines, and more particularly to those machines employing one or more surface maintenance or conditioning appliances or tools to perform a floor cleaning task.
In general, proper carpet maintenance involves regular vacuuming and periodic cleaning to remove soil by methods such as hot water extraction, shampooing, bonnet cleaning, foam cleaning, etc. Some of the soil is loosely found between carpet fibers while other soil is held upon the carpet fibers by some means such as electrostatic forces, van der Waals forces, or oil bonding. Still other soil is mechanically trapped by carpet fibers. Regular vacuuming is essential as it removes some of the loose soil that damages the fibers. Vacuuming maintains the surface appearance of a carpet and keeps the level of soil in the pile at an acceptable level. Vacuuming removes only particulate soil and some unbound or loosely bound surface dirt, however, therefore, other methods of cleaning are periodically required to improve the appearance of the carpet. Wet cleaning methods are required to remove oils, greases, bound dirt, and other forms of matter that cause soiling on carpet. These methods are often used by professional cleaners and trained personnel.
One type of surface maintenance machine for carpet cleaning is referred to as a bonnet cleaner. Bonnet cleaners employ an absorbent bonnet or pad (hereinafter referred to as the xe2x80x9cpadxe2x80x9d) attached to a rotary driver for rotating the pad about an axis generally perpendicular to the carpet surface. Most commonly a solution of cleaning liquid is sprayed directly onto the carpet and then the rotating pad is used to agitate the wetted carpet. This action transfers soil from the carpet onto the pad. Since the pad is commonly two-sided, the pad may be reversed once one side of the pad gets saturated or soiled to a selected level. The pad may be periodically replaced and later cleaned depending upon the application and wear characteristics of the pad.
The soil transfer process of the bonnet cleaners may be characterized as a xe2x80x9ccircular engagement processxe2x80x9d since the pad rotates in a circular motion essentially in the plane of the carpet surface. The method employed by bonnet cleaners has the advantage of being fast drying if a relatively small amount of cleaning liquid is employed. However the process is fundamentally unstable since the rotating pad starts out clean and becomes less and less effective as a cleaning tool as it collects soil. Additional limitations of bonnet cleaners include transferring soil from soiled areas to relatively cleaner areas, leaving much of the cleaning fluid in the carpet, and having the potential to damage the carpet. With respect to the latter, some carpets, particular twisted ply variations, may be damaged by aggressive engagement with the rotating pad. Additionally, the bonnet cleaning process is a relatively labor intensive process since the pad requires frequent soil monitoring and frequent removal of soiled pads.
Yet another limitation of bonnet cleaners is the relatively uncontrolled use of cleaning liquid in the carpet cleaning process as some areas of the carpet may receive more cleaning liquid spray than other areas. Reliance on operator spraying of cleaning liquid to the carpet surface may result in over wetting of some areas and under wetting of other areas.
Another type of surface maintenance machine designed for carpet cleaning is referred to as a xe2x80x9chot water extractorxe2x80x9d or an xe2x80x9cextractor machine.xe2x80x9d Extractor machines are commonly used for deep carpet cleaning. In general, an extractor is a transportable self-contained device which (i) sprays cleaning liquid directly onto the carpet to create a wetted carpet portion, (ii) agitates the wetted portion with a brush, and (iii) removes some of the cleaning liquid and soil in the carpet through a vacuum system. Generally, the extraction process applies a relatively large quantity of cleaning liquid on the carpet. While the vacuum system recovers a portion of the applied cleaning liquid, a significant portion is retained by the carpet. As a consequence, carpet drying times are substantially longer than in the bonnet cleaning process.
FIG. 4 illustrates functions of a conventional extractor machine 80. In general, extractor 80 is a transportable self-contained device which (i) sprays cleaning liquid directly onto the carpet to create a wetted carpet portion, (ii) agitates the wetted portion with a brush, and (iii) removes some of the cleaning liquid and soil in the carpet through a vacuum system. Components of a conventional extractor machine 80 include a solution tank 82, a pump 84 for conveying solution from tank 82, and a spray nozzle 86 for spraying solution onto a floor surface 88. A brush motor 90 powers a brush 92 which engages the floor surface 88. Subsequently, as the machine is move in an operational direction, a pickup tool or xe2x80x9cextractorxe2x80x9d 94 engages the floor surface 88 to remove soiled solution from the surface 88. A vacuum fan 96 and recovery tank 98 are provided to respectively remove and receive soiled solution from surface 88. Additional features of an extractor machine are disclosed in U.S. Pat. No. 4,956,891, assigned to Tennant Company, and incorporated herein by reference.
Another type of surface maintenance machine intending for carpet cleaning has been developed by Tennant Company and is the subject of U.S. application Ser. No. 10/081,374, entitled xe2x80x9cApparatus and Method for Cleaning Fabrics, Floor Coverings, and Bare Floor Surfaces Utilizing a Soil Transfer Cleaning Mediumxe2x80x9d, incorporated by reference herein. This method does not spray the water directly onto the surface being cleaned at all. Instead, In accordance with that invention, a revolving cleaning medium, such as a cylindrical roll, is wetted and wiped against a surface intended to be cleaned. In general, this method of cleaning includes the steps of (i) wetting a revolving cleaning medium with a cleaning solution, (ii) removing at least some of the cleaning liquid from the revolving cleaning medium directly after wetting by way of a moisture extraction device, and (iii) wiping the surface with the revolving cleaning medium so as to transfer soil from the surface to the revolving cleaning medium and subsequently removing transferred soil from the revolving cleaning medium.
FIG. 5 illustrates a soil transfer roll carpet cleaning machine 102, such as taught in U.S. application Ser. No. 10/081,374. Components of a soil transfer roll cleaning machine 102 include a solution tank 104, a pump 106 for conveying solution from tank 104, and a spray nozzle 108 for spraying solution onto cleaning mediumxe2x80x94rolls 100. Motors 110 drive rolls 100 which engage the floor surface 112. Extractors 114 engage the rolls 100 to remove soiled solution from rolls 100. A vacuum fan 116 and recovery tank 118 are provided to respectively remove and receive soiled solution 120 from rolls 100. In a preferred operation, one portion of the cleaning medium 100 is wetted with cleaning liquid, while another portion is being extracted to remove soil and cleaning liquid therefrom, and while yet another portion is being wiped against the surface to transfer soil from the surface to the cleaning medium 100. The process continues in a revolving or cyclical manner so that each portion of the cleaning medium 100 is sequentially wetted, extracted, and wiped against the surface
An object of the present invention is the provision of a dual mode carpet cleaning machine. Another object of one embodiment of the present invention is to significantly decrease the amount of cleaning solution applied to a carpet surface during at least one mode of operation. The benefits of reduced solution usage are 3-fold. First, reduced solution usage lowers the cost of operation since it requires less clean water and less cleaning chemical to clean a given area and it produces less waste water to be disposed of after cleaning. Second, reduced solution usage increases productivity since the cleaning equipment can be operated for longer periods of time without stopping to refill or empty the solution tanks. Third, reduced solution usage results in a significantly shorter dry time after the cleaning process has been completed and before the area can be reopened for use.
Yet another object of the present invention is the provision of a cleaning process and apparatus for cleaning a variety of surfaces, including but not limited to floor surfaces, stairways, walls, and upholstered furniture or other fabric surfaces.
In accordance with one embodiment of the present invention, a transportable device is utilized to perform at least two different cleaning process on a carpeted surface. The device may be a relatively portable machine having a cleaning liquid tank, a soiled solution recovery tank, a vacuum system, and cleaning head. The cleaning head may include a floor pickup tool and brushes or rolls and associated drive mechanism. Vacuum extractor tools may be used to engage the rolls or other surface to remove soil and at least some of the soiled cleaning liquid. Common parts such as motors and brushes may be utilized during the two different cleaning processes.
In accordance with one embodiment of the invention in a first mode of operation a carpet extraction process is performed. In the first mode of operation a cleaning solution is sprayed onto the surface and/or brushes and the brushes agitate the floor surface to transfer soil from the surface into a soiled cleaning solution. The soiled cleaning solution is subsequently removed from the surface via a vacuum extractor tool and transported into a soiled solution recovery tank. In a second mode of operation a soil transfer roll cleaning process is performed utilizing revolving soil transfer rolls having portions of each roll being successively wetted, extracted, and wiped against a surface intended to be cleaned.